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linux/mm
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Liam R. Howlett bed76bec31 mm: relocate the page table ceiling and floor definitions 
Patch series " Remove XA_ZERO from error recovery of dup_mmap()", v3.

It is possible that the dup_mmap() call fails on allocating or setting up
a vma after the maple tree of the oldmm is copied.  Today, that failure
point is marked by inserting an XA_ZERO entry over the failure point so
that the exact location does not need to be communicated through to
exit_mmap().

However, a race exists in the tear down process because the dup_mmap()
drops the mmap lock before exit_mmap() can remove the partially set up vma
tree.  This means that other tasks may get to the mm tree and find the
invalid vma pointer (since it's an XA_ZERO entry), even though the mm is
marked as MMF_OOM_SKIP and MMF_UNSTABLE.

To remove the race fully, the tree must be cleaned up before dropping the
lock.  This is accomplished by extracting the vma cleanup in exit_mmap()
and changing the required functions to pass through the vma search limit. 
Any other tree modifications would require extra cycles which should be
spent on freeing memory.

This does run the risk of increasing the possibility of finding no vmas
(which is already possible!) in code that isn't careful.

The final four patches are to address the excessive argument lists being
passed between the functions.  Using the struct unmap_desc also allows
some special-case code to be removed in favour of the struct setup
differences.


This patch (of 11):

pgtables.h defines a fallback for ceiling and floor of the page tables
within the CONFIG_MMU section.  Moving the definitions to outside the
CONFIG_MMU allows for using them in generic code.

[akpm@linux-foundation.org: remove stray newline, per SeongJae]
Link: https://lkml.kernel.org/r/20260121164946.2093480-1-Liam.Howlett@oracle.com
Link: https://lkml.kernel.org/r/20260121164946.2093480-2-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-02-12 15:42:53 -08:00
..
damon mm/damon/stat: remove __read_mostly from memory_idle_ms_percentiles 2026-02-06 15:47:17 -08:00
kasan kasan: remove unnecessary sync argument from start_report() 2026-01-31 14:22:52 -08:00
kfence mm: replace use of system_unbound_wq with system_dfl_wq 2026-01-31 14:22:39 -08:00
kmsan mm: kmsan: add test_uninit_page 2026-01-26 20:02:32 -08:00
tests sparc/mm: export symbols for lazy_mmu_mode KUnit tests 2026-01-31 14:22:40 -08:00
backing-dev.c mm: add WQ_PERCPU to alloc_workqueue users 2026-01-31 14:22:39 -08:00
balloon.c mm: rename CONFIG_BALLOON_COMPACTION to CONFIG_BALLOON_MIGRATION 2026-01-31 14:22:36 -08:00
bootmem_info.c mm/sparse: allow for alternate vmemmap section init at boot 2025-03-16 22:06:27 -07:00
cma.c mm/cma: replace snprintf with strscpy in cma_new_area 2026-02-06 15:47:15 -08:00
cma.h mm: cma: set early_pfn and bitmap as a union in cma_memrange 2025-05-22 14:55:36 -07:00
cma_debug.c mm: cma: simplify cma_maxchunk_get() 2025-07-24 19:12:36 -07:00
cma_sysfs.c
compaction.c mm/compaction: fix low_pfn advance on isolating hugetlb 2025-09-28 11:51:29 -07:00
debug.c mm: constify __dump_folio() arguments 2025-11-20 13:43:57 -08:00
debug_page_alloc.c mm/debug_page_alloc: improve error message for invalid guardpage minorder 2025-05-12 23:50:38 -07:00
debug_page_ref.c
debug_vm_pgtable.c mm: debug_vm_pgtable: add debug_vm_pgtable_free_huge_page() 2026-01-26 20:02:27 -08:00
dmapool.c docs: dma-api: replace consistent with coherent 2025-07-01 13:25:36 -06:00
dmapool_test.c mm: add SPDX id lines to some mm source files 2026-02-06 15:47:16 -08:00
early_ioremap.c mm/early_ioremap: clean up the use of WARN() for debugging 2026-01-26 20:02:26 -08:00
execmem.c mm: remove PMD alignment constraint in execmem_vmalloc() 2025-09-28 11:51:31 -07:00
fadvise.c mm: rename filemap_fdatawrite_range_kick to filemap_flush_range 2025-10-29 15:50:42 +01:00
fail_page_alloc.c
failslab.c
filemap.c ARM: 2025-12-05 17:01:20 -08:00
folio-compat.c mm: add SPDX id lines to some mm source files 2026-02-06 15:47:16 -08:00
gup.c mm/gup: remove no longer used gup_fast_undo_dev_pagemap 2026-01-20 19:24:49 -08:00
gup_test.c mm: add SPDX id lines to some mm source files 2026-02-06 15:47:16 -08:00
gup_test.h
highmem.c mm/highmem: fix __kmap_to_page() build error 2026-01-31 14:22:38 -08:00
hmm.c Significant patch series in this merge are as follows: 2025-12-05 13:52:43 -08:00
huge_memory.c migrate: replace RMP_ flags with TTU_ flags 2026-01-26 20:02:33 -08:00
hugetlb.c hugetlb: increase hugepage reservations when using node-specific "hugepages=" cmdline 2026-01-31 14:22:52 -08:00
hugetlb_cgroup.c mm: add SPDX id lines to some mm source files 2026-02-06 15:47:16 -08:00
hugetlb_cma.c mm: hugetlb_cma: mark hugetlb_cma{_only} as __ro_after_init 2026-01-31 14:22:43 -08:00
hugetlb_cma.h mm: hugetlb: allocate frozen pages for gigantic allocation 2026-01-26 20:02:28 -08:00
hugetlb_internal.h mm/hugetlb: extract sysctl into hugetlb_sysctl.c 2025-11-20 13:43:57 -08:00
hugetlb_sysctl.c mm, hugetlb: implement movable_gigantic_pages sysctl 2026-01-20 19:24:50 -08:00
hugetlb_sysfs.c mm/hugetlb: extract sysfs into hugetlb_sysfs.c 2025-11-20 13:43:57 -08:00
hugetlb_vmemmap.c Revert "mm/hugetlb: deal with multiple calls to hugetlb_bootmem_alloc" 2026-01-26 20:02:20 -08:00
hugetlb_vmemmap.h mm/hugetlb: do pre-HVO for bootmem allocated pages 2025-03-16 22:06:29 -07:00
hwpoison-inject.c mm/hwpoison: decouple hwpoison_filter from mm/memory-failure.c 2025-09-21 14:22:21 -07:00
init-mm.c mm: rename cpu_bitmap field to flexible_array 2026-01-19 12:30:00 -08:00
internal.h mm: move pte table reclaim code to memory.c 2026-02-06 15:47:19 -08:00
interval_tree.c
ioremap.c
Kconfig mm: make PT_RECLAIM depends on MMU_GATHER_RCU_TABLE_FREE 2026-02-06 15:47:19 -08:00
Kconfig.debug mm: fix DEBUG_RODATA_TEST indentation in Kconfig 2025-11-29 10:41:09 -08:00
khugepaged.c mm: khugepaged: fix NR_FILE_PAGES and NR_SHMEM in collapse_file() 2026-02-06 15:47:15 -08:00
kmemleak.c mm: fix possible deadlock in kmemleak 2025-09-01 17:11:37 -07:00
ksm.c mm/ksm: fix pte_unmap_unlock of wrong address in break_ksm_pmd_entry 2025-12-23 11:23:17 -08:00
list_lru.c memcg: introduce private id API for in-kernel users 2026-01-26 20:02:23 -08:00
maccess.c mm: unexport globally copy_to_kernel_nofault 2025-07-09 22:42:22 -07:00
madvise.c mm, swap: cleanup swap entry management workflow 2026-01-31 14:22:56 -08:00
Makefile mm: move pte table reclaim code to memory.c 2026-02-06 15:47:19 -08:00
mapping_dirty_helpers.c mm/dirty: replace READ_ONCE() with pudp_get() 2025-11-16 17:27:58 -08:00
memblock.c mm: fix minor spelling mistakes in comments 2026-01-20 19:24:48 -08:00
memcontrol-v1.c memcg: introduce private id API for in-kernel users 2026-01-26 20:02:23 -08:00
memcontrol-v1.h memcg: introduce private id API for in-kernel users 2026-01-26 20:02:23 -08:00
memcontrol.c mm/vmscan: fix demotion targets checks in reclaim/demotion 2026-02-12 15:42:52 -08:00
memfd.c mm: add SPDX id lines to some mm source files 2026-02-06 15:47:16 -08:00
memfd_luo.c mm: memfd_luo: restore and free memfd_luo_ser on failure 2026-01-26 19:03:47 -08:00
memory-failure.c Merge branch 'mm-hotfixes-stable' into mm-stable to pick up "mm/shmem, 2026-01-31 14:20:03 -08:00
memory-tiers.c mm/vmscan: select the closest preferred node in demote_folio_list() 2026-02-12 15:42:53 -08:00
memory.c mm: folio_zero_user: open code range computation in folio_zero_user() 2026-02-12 15:42:53 -08:00
memory_hotplug.c mm: rename CONFIG_BALLOON_COMPACTION to CONFIG_BALLOON_MIGRATION 2026-01-31 14:22:36 -08:00
mempolicy.c mm: use nodes_and() return value to simplify client code 2026-01-26 20:02:36 -08:00
mempool.c slab updates for 6.19 2025-12-03 11:53:47 -08:00
memremap.c mm/zone_device: reinitialize large zone device private folios 2026-01-26 19:03:48 -08:00
memtest.c
migrate.c mm: rename CONFIG_BALLOON_COMPACTION to CONFIG_BALLOON_MIGRATION 2026-01-31 14:22:36 -08:00
migrate_device.c mm: fix minor spelling mistakes in comments 2026-01-20 19:24:48 -08:00
mincore.c mm: replace remaining pte_to_swp_entry() with softleaf_from_pte() 2025-11-24 15:08:52 -08:00
mlock.c mm: update vma_modify_flags() to handle residual flags, document 2025-11-20 13:43:58 -08:00
mm_init.c Merge branch 'mm-hotfixes-stable' into mm-stable to pick up "mm/shmem, 2026-01-31 14:20:03 -08:00
mm_slot.h
mmap.c mm: softdirty: add pgtable_supports_soft_dirty() 2025-11-24 15:08:54 -08:00
mmap_lock.c mm/vma: improve and document __is_vma_write_locked() 2026-01-31 14:22:51 -08:00
mmu_gather.c mm: add SPDX id lines to some mm source files 2026-02-06 15:47:16 -08:00
mmu_notifier.c Update Christoph's Email address and make it consistent 2025-05-12 23:50:31 -07:00
mmzone.c mm: introduce memdesc_flags_t 2025-09-13 16:55:07 -07:00
mprotect.c mm: introduce generic lazy_mmu helpers 2026-01-20 19:24:33 -08:00
mremap.c mm: fix minor spelling mistakes in comments 2026-01-20 19:24:48 -08:00
mseal.c mm: fix minor spelling mistakes in comments 2026-01-20 19:24:48 -08:00
msync.c
nommu.c mm/nommu: convert kobjsize() to folios 2025-09-13 16:54:46 -07:00
numa.c mm/numa: remove unnecessary local variable in alloc_node_data() 2025-05-12 23:50:38 -07:00
numa_emulation.c mm: numa,memblock: Use SZ_1M macro to denote bytes to MB conversion 2025-08-20 16:31:23 +03:00
numa_memblks.c mm: fix minor spelling mistakes in comments 2026-01-20 19:24:48 -08:00
oom_kill.c mm: fix OOM killer inaccuracy on large many-core systems 2026-01-31 14:22:37 -08:00
page-writeback.c mm/block/fs: remove laptop_mode 2026-01-20 19:24:47 -08:00
page_alloc.c mm: page_alloc: optimize pfn_range_valid_contig() 2026-01-31 14:22:42 -08:00
page_counter.c page_counter: track failcnt only for legacy cgroups 2025-03-17 00:05:35 -07:00
page_ext.c mm,page_ext: derive the node from the pfn 2025-07-13 16:38:16 -07:00
page_frag_cache.c
page_idle.c mm/rmap: extend rmap and migration support device-private entries 2025-11-24 15:08:48 -08:00
page_io.c mm: fix minor spelling mistakes in comments 2026-01-20 19:24:48 -08:00
page_isolation.c mm: page_isolation: introduce page_is_unmovable() 2026-01-31 14:22:42 -08:00
page_owner.c mm/page_owner: fix memory leak in page_owner_stack_fops->release() 2025-12-23 11:23:17 -08:00
page_poison.c
page_reporting.c mm: fix minor spelling mistakes in comments 2026-01-20 19:24:48 -08:00
page_reporting.h
page_table_check.c mm: provide address parameter to p{te,md,ud}_user_accessible_page() 2026-01-26 20:02:35 -08:00
page_vma_mapped.c mm: eliminate further swapops predicates 2025-11-24 15:08:52 -08:00
pagewalk.c mm/pagewalk: use min() to simplify the code 2026-01-31 14:22:52 -08:00
percpu-internal.h
percpu-km.c mm/mm/percpu-km: drop nth_page() usage within single allocation 2025-09-21 14:22:04 -07:00
percpu-stats.c mm: remove outdated filename comment in percpu-stats.c 2025-07-13 16:38:23 -07:00
percpu-vm.c kmsan: remove hard-coded GFP_KERNEL flags 2025-11-16 17:27:54 -08:00
percpu.c percpu: add double free check to pcpu_free_area() 2026-01-31 14:22:52 -08:00
pgalloc-track.h
pgtable-generic.c mm/huge_memory: add device-private THP support to PMD operations 2025-11-24 15:08:48 -08:00
process_vm_access.c
ptdump.c mm/ptdump: replace READ_ONCE() with standard page table accessors 2025-11-16 17:27:52 -08:00
readahead.c mm/readahead: fix typo in comment 2026-02-06 15:47:16 -08:00
rmap.c mm: add SPDX id lines to some mm source files 2026-02-06 15:47:16 -08:00
rodata_test.c
secretmem.c Significant patch series in this merge are as follows: 2025-12-05 13:52:43 -08:00
shmem.c mm: add SPDX id lines to some mm source files 2026-02-06 15:47:16 -08:00
shmem_quota.c
show_mem.c mm/vmscan: add tracepoint and reason for kswapd_failures reset 2026-01-31 14:22:38 -08:00
shrinker.c
shrinker_debug.c memcg: rename mem_cgroup_ino() to mem_cgroup_id() 2026-01-26 20:02:25 -08:00
shuffle.c
shuffle.h
slab.h mm/slab: introduce kvfree_rcu_barrier_on_cache() for cache destruction 2025-12-07 18:09:54 +01:00
slab_common.c slab fix for 6.19-rc1 2025-12-11 08:54:08 +09:00
slub.c mm: add WQ_PERCPU to alloc_workqueue users 2026-01-31 14:22:39 -08:00
sparse-vmemmap.c mm: replace READ_ONCE() with standard page table accessors 2025-11-16 17:27:56 -08:00
sparse.c mm/memory_hotplug: Remove MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers 2025-10-14 14:24:53 +02:00
swap.c mm: fix minor spelling mistakes in comments 2026-01-20 19:24:48 -08:00
swap.h mm, swap: drop the SWAP_HAS_CACHE flag 2026-01-31 14:22:57 -08:00
swap_cgroup.c mm: swap_cgroup: remove double initialization of locals 2025-03-17 22:06:58 -07:00
swap_state.c mm, swap: drop the SWAP_HAS_CACHE flag 2026-01-31 14:22:57 -08:00
swap_table.h mm, swap: use a single page for swap table when the size fits 2025-09-21 14:22:25 -07:00
swapfile.c mm, swap: remove no longer needed _swap_info_get 2026-01-31 14:22:58 -08:00
truncate.c vfs-6.19-rc1.folio 2025-12-01 10:26:38 -08:00
usercopy.c usercopy: Remove folio references from check_heap_object() 2025-11-13 11:01:08 +01:00
userfaultfd.c mm, swap: check swap table directly for checking cache 2026-01-31 14:22:57 -08:00
util.c mm: add ability to take further action in vm_area_desc 2025-11-16 17:28:12 -08:00
vma.c mm/rmap: separate out fork-only logic on anon_vma_clone() 2026-01-26 20:02:22 -08:00
vma.h mm: cleanup vma_iter_bulk_alloc 2026-01-20 19:24:50 -08:00
vma_exec.c mm: softdirty: add pgtable_supports_soft_dirty() 2025-11-24 15:08:54 -08:00
vma_init.c Summary of significant series in this pull request: 2025-10-02 18:18:33 -07:00
vma_internal.h mm: relocate the page table ceiling and floor definitions 2026-02-12 15:42:53 -08:00
vmalloc.c Merge branch 'mm-hotfixes-stable' into mm-stable to pick up "mm/shmem, 2026-01-31 14:20:03 -08:00
vmpressure.c memcg: convert memcg->socket_pressure to u64 2025-07-24 19:12:32 -07:00
vmscan.c mm/vmscan: select the closest preferred node in demote_folio_list() 2026-02-12 15:42:53 -08:00
vmstat.c mm: add WQ_PERCPU to alloc_workqueue users 2026-01-31 14:22:39 -08:00
workingset.c memcg: introduce private id API for in-kernel users 2026-01-26 20:02:23 -08:00
zpdesc.h mm: zpdesc: minor naming and comment corrections 2025-09-21 14:21:59 -07:00
zsmalloc.c zsmalloc: make common caches global 2026-02-06 15:47:17 -08:00
zswap.c mm/zswap: use %pe to print error pointers 2026-02-06 15:47:16 -08:00